Tube bending tools



Feb. 22, 1966 B'ECK ETAL 3,235,032

TUBE BENDING TOOLS Filed July 24. 1961 2 Sheets-Sheet 1 INVENTORS EDWARDBECK 8 EDWARD J. CATOR FIG. 2 ,9

ATTORNEYS Feb. 22, 1966 E. B-ECK ETAL 3,236,082

TUBE BENDING TOOLS Filed July 24. 1961 2 Sheets-Sheet z FIG. 3

INVENTORS 5 EDWARD BECK 8 BY EDWARD J. CATOR ATTORNEYS United StatesPatent 3,236,082 TUBE BENDING TOOLS Edward Beck, Cleveland, Ohio, andEdward J. Cator,

Rochester, N.Y., assignors to Crawford Fitting Company, Cleveland, Ohio,a corporation of Ohio Filed July 24, 1961, Ser. No. 127,447 4 Claims.(Cl. 72-149) This invention relates to improvements in hand operatedtube bending tools and consists of the combination, construction andarrangements herein described and claimed.

With prior tube or conduit benders of the type herein described it hasbeen found that the tube after bending has an ovality of as much as .050inch. This was noted with copper tubing. It also was noted that steeltubing would buckle during bending.

It is a prime object of this invention to provide a hand operated tubebending tool which will operate to minimize ovality in the tube shape,as well as to eliminate buckling in the tube wall, during bendingoperations.

A further object of the invention is to provide a device by which tubesmay be bent Without friction on the outer diameter thereof.

It is also an object of the invention to provide a tube bending tool bywhich the man power required for operating the tool for bendingoperations may be reduced to a minimum.

Other objects relating to the advantages obtained in the structure andoperation of the tube bending tool constituting this invention Willbecome apparent in the description to follow.

The invention is illustrated in the accompanying drawings forming a partof this application, in which:

FIG. 1 is a perspective view of the tube bending tool constituting thisinvention, shown in the loading or threading position;

FIG. 2 is an enlarged top plan view of the tool shown in an alternativeposition or operating position;

FIG. 3 is a vertical sectional view on the line 3-3 of FIG. 2 looking inthe direction of the arrows;

FIG. 4 is a fragmentary view in partial elevation and partially incross-section on the line 4-4 of FIG. 3;

FIG. 5 is a detail sectional view on the line 5-5 of FIG. 3 and lookingin the direction of the arrows, and

FIG. 6 is a detail vertical sectional view illustrating the constructionof the U-frame which carries the idler rollers for tube bendingoperations.

Referring further to the drawings, and more particularly to FIGS. 1 and2, 10 indicates in general a case construction for housing gears forhand operation of the tool. The gear case comprises a cup-shaped base11, and a cover plate 12 which is secured to the base by the socket headcap screws 13, or the like.

The base 11 has depending from its bottom, centrally thereof, a block 14with fiat faces 15 suitable for apply-. ing the jaws of a vise (notshown) for holding the tool on a bench or preferably, on a single columnto provide space for compound angle bending. The base member 11 and thecover plate 12 provide an annular space 16 for housing the bevel gears17 and 18 as best seen in FIG. 3. The cover plate 12 has a dependingannular flange 12' which fits in an annular recess formed in the iceadjacent inner edge of the base member 11. The gear 17 is fixed to theinner end of the stub shaft or crank shaft 19 by a pin 20. The shaft 19is journaled in the side wall of the base member 11 as best shown inFIG. 3; its outer end is axially recessed for removably receiving thefree end of the squared crank arm 21 which carries a hand grasp roller22 at its outer end.

Gear 1 8 is rotatably supported by the stub shaft 23 which has its lowerend journaled in the bottom of the base member 11, as indicated at 24.The hub 25 of the gear 18 is fixed upon the shaft 23 by a pin 26, andthe hub is journaled in the cover plate 12 as indicated at 27.

The shaft 23 extends above the cover plate 12 and the forming roll 28 isfixed thereon by a spline or key 29. The plate 30, screw 31, and spline29 lock the forming roll against movement on the upper end of the shaft23.

Near the outer edge on the upper surface of the circular cover late 12is provided a degree scale 32 from zero to 180 degrees. The gear casemember 11 and the lower surface of the cover plate 12 are provided withregistrating grooves 33 and 34 respectively which correspond in lengthto the degree scale 32.

The upper edge of the gear case member 11 is provided with an outerrecess or ledge which affords an annular slot 35 with the registeringlower edge surface of the cover plate 12 in which bolt 36 can freelyslide. Bolt 36 has fixed on its inner end a head adapted to slide in thearcuate slot or channel formed by the grooves 33 and 34. The outer endof the bolt 36 has threaded thereon a knurled head 37 which can be usedfor locking the pointer 38 carried by the bolt 36 at the desired degreeon the scale 32.

The forming roll 28 is formed with an arcuate peripheral groove whichterminates at its ends in a flat section or length 40 (FIG. 4). The flatsection is provided with a central threaded bore for receiving thereduced threaded end 41 of the tube clamp bar 42. The inner end of thebar 42 is also reduced for pivotally supporting the arcuately shapedtube clamping jaw 43. The bar 42 also carries a stop 44 whichconstitutes a plug threaded into a suitable bore in the lower surface ofthe bar and adapted to form a stop with the pointer member 38 for thescale 32.

The bar 42 has an extension 45 threadedly secured to its outer end. Theextension and base are provided with a graduated continuous scale 46which begins at the inner end of the bar 42.

The bar extension 45 carries an adjustable tube stop 47 comprising apair of hinged jaws 48 which may be clamped at any point on the scale 46by the thumb screw 49. The threaded hole 50 in the jaw 47 is provided toreceive exchangeably a tube abutment 50' which has a centering tip 51.To adapt tube abutment 50' to various wall thicknesses of availabletubing material, several of said tube abutments 58' can be employed withvarying diameters of the centering tip 51.

The cover plate 12 supports a U-frame member 52 Which carries the idlertube rollers 53 and 54. The roller 53 is journaled by the shoulder screwwhich also serves for pivotally securing the same end of the framemember 52 to the cover plate 12 (FIG. 6). The roller 54 is supportedrotatably by a sleeve 55' which in turn encloses a spring loaded plunger56 adapted to seat in a sleeve lined bore 57 in the cover plate 12 forholding the roller 54 in operative position with respect to the formingroll 28 for tube bending operations.

The plunger head 58 threaded on the outer end of the plunger 56 servesfor releasing the roller from its operative position, and permits theframe member 52 to be swung to the position illustrated in FIG. 2. Thelast named position of the frame 52 permits easy placement of a tube inthe bending tool as well as easy withdrawal of the tube after beingbent.

It should be noted that the peripheral groove formed in each of rollers53 and 54 is the same in shape and depth as the groove 39 of the formingroll 28. As illustrated in FIGS. 2 and 3 the tube 60 is fully enclosedwithin the peripheral complementary grooves of the mandrel 28 and theroller 54. This is important in the operation of the tool disclosedherein for minimizing ovality or buckling of the tube during bendingoperations.

It should be noted also that the rollers 53 and 54 as well as themandrel 28 can be replaced easily with others which have peripheralgrooves suitable for the outside diameter of the large or smaller tubesto be bent.

Before the tube bending tool described herein can be used it must, ofcourse, be solidly secured by a vise, i.e., the jaws of the viseclamping the depending block 14. The block permits the tool to bearranged in the best posi tion for operating the handle 21, or for otherworking purposes of the operator.

Assuming it is desired to fashion a tube pattern for mass production,the plunger 56 is operated to free the frame 52 on its shoulder screw 55and the frame is pivoted thereabout to the outward position shown inphantom in FIG. 2. The crank arm 21 is operated to bring the formingroll 28 into posiiton for placing the stop 44 carried by bar 42 at zeropoint on scale 32, as shown in FIG. 1. A tube is then positioned in thegroove 39 of the forming roll with the leading end of the tube beingbrought past the idler roll 53 and forming roll 28 a sufficient degreeso that it will be held in the groove 39 of the forming roll 28 uponengagement by the arcuate clamping jaw member 43. The frame 52 is swunginwardly on its shoulder screw 55 until the spring-loaded plunger 56seats itself in the detent socket 57 and thus the roller is brought intooperating relation with the forming roll 28, i.e., the forming roll andassociated idler grooves fully surround and support the tube wall asshown in FIG. 3.

The pointer 38 is set for the angle the tube is to be bent. For example,if a 90 angle is desired, the setting would be as shown in FIG. 1. Withthe positioning of roller 54, the roller 53 also is in position for apipe bending operation.

The crank 21 is then rotated, rotating bevel gear 17, thereby impartingrotation to bevel gear 18. The forming roll 28 and bevel gear 18 areattached to the shaft 23 so that rotation thereof imparts rotation tothe bar member 42, thus rotating the tube carried by the tube abutment50 to impart a bending motion thereto. The crank is rotated until thestop means 44 abuts the pointerstop member 38, as best seen in FIG. 2.At this point .a 90 bend will be produced in the end of the tube whichwill be free of buckling and the ovality thereof minimized. The springloaded plunger 56 is next lifted to free the frame 52 for outwardswinging movement of the roller 54, and after the clamping jaw 43 hasbeen swung free of engagement with the tube end, the tube may be easilywithdrawn from the tool. The straight end of the tube now can be cut thedesired length from the center of the bend, i.e., to form the tubepattern-desired, and the pattern can be returned to the tool with itsstraight portion providing a leading end.

The stop 47 now is set at a point on the scale 46 which will bring itsabutment member 50' against the end of the tube 60 as shown in FIG. 2.The tool now is ready for mass production of the pattern described abovewithout resetting.

In tube bending operations the guide shoe or roller 54 in conjunctionwith the mandrel 28 and the roller or idler 53 operate to minimizeovality in the tubes bent, and to prevent buckling in the bend Zone bysupporting the tube Wall substantially completely about its periphery.The bevel gears 17 and 18 in the ratio illustrated show operation of thetool for bending purposes without the expenditure of large amounts ofmanpower, even where used with heavy wall tubes. The tool as a whole,including the bend setting means, as well as the tube stop means to beused for mass production, are simple in construction and operation withthe result that .a highly efficient tool is provided, particularly formass production purposes. Also, the tool is relatively inexpensive tomanufacture and sufficiently rugged to withstand long usage,

While the preferred construction and operation of this invention are setforth herein, it is to be understood that said invention is not to be solimited as indicated by the appended claims.

We claim:

1. A tube bending tool comprising a gear case forming a cup shaped base,cover plate means fixedly attached to said base, shaft means rotatablysupported in said case and extending through said cover plate, firstgear means on said shaft, said first gear means having an axiallyextending hub portion journalled in said cover plate, second gear meansjournalled in said cup shaped base and cooperating with said first gearmeans, crank means interfitted with said second gear to allow manualrotation thereof, a forming roll carried by the end of the shaftextending through said plate, a pivotable U frame carried by said coverplate and being attached thereto by pivot means, said U frame beingspaced from said forming roll, a pair of idler rollers carried by said Uframe, one of said rollers being rotatable about a sleeve, a springbiased plunger means carried by said sleeve and having a plunger headattached at one end thereof, bore means in said cover plate to receivethe other end of said plunger when said U frame is pivoted towards saidforming roll, said plunger being removable from said bore thereby toallow pivoting of said U frame to release the other roller from itsoperative position, marking means on said cover plate to indicate theangle of bend, pointer means slidably carried about the periphery ofsaid case to cooperate with said marking means, bar means carried bysaid forming roll, said bar means having stop means thereon to cooperatewith said pointer means whereby overbending will be avoided.

2. The tube bender of claim 1 wherein said bar means carried by theforming roll has tube abutment means thereon, said abutment meansincluding a centering tip adapted to receive a free end of a tube.

3. The tube bender of claim 2 wherein the tube abutment means isadjustable on said bar means, and marker means on said bar meanscooperating with said adjustable tube abutment means whereby the lengthof tube from said bend may be readily set.

4. A manually operable tube bending tool comprising a cup shaped basemember having a clamping block fixedly secured to and dependingtherefrom, cover plate means overlying said cup shaped base member,means releasably securing said cover plate to said base member therebyto form a hollow compartment therebetween, shaft means rotatablysupported by said base and cover plate, said shaft extending above saidcover plate, gear means mounted for rotation on said shaft, said gearmeans being disposed below said cover plate and having a hub portionjournalled therein, a forming roll having a concavity formed in the sidethereof, said forming roll being fixedly secured to the end of the shaftextending through said cover plate for rotation therewith, a U shapedframe member pivotably secured to said cover plate, said U shaped framemember carrying a first idler roll which is rotatable about the pivot ofthe U frame, a second idler roll carried by said U shaped frame memberspaced from said first idler roll and said forming roll, plunger meanspassing through said second idler roll and having an end thereofreceived in a bore in said cover plate, said plunger means beingretractable from said bore whereby said U shaped member may be pivotedto increase the distance between said second idler roll and said formingroller, an extension bar carried by said forming roll for rotationtherewith, tube clamp means pivotable about said bar to engage saidtube, means on said bar to releasably receive the leading end of aconduit, said means including a conduit abutment for engagement with theleading end of said conduit, means releasably securing said abutmentmember on said bar, said means cooperating with a slidable pointer meanscarried by said case to form a stop means to limit the degree ofrotational movement of said bar.

References Cited by the Examiner UNITED STATES PATENTS 749,029 1/ 1904Condon 15340 2,762,415 9/1956 Franck 15340 3,004,583 10/1961 Zuccala eta1 15346 10 CHARLES W. LANHAM, Primary Examiner.

WHITMORE A. WILTZ, Examiner.

1. A TUBE BENDING TOOL COMPRISING A GEAR CASE FORMING A CUP SHAPED BASE, COVER PLATE MEANS FIXEDLY ATTACHED TO SAID BASE, SHAFT MEANS ROTATABLY SUPPORTED IN SAID CASE AND EXTENDING THROUGH SAID COVER PLATE, FIRST GEAR MEANS ON SAID SHAFT, SAID FIRST GEAR MEANS HAVING AN AXIALLY EXTENDING HUB PORTION JOURNALLED IN SAID COVER PLATE, SECOND GEAR MEANS JOURNALLED IN SAID CUP SHAPED BASE AND COOPERATING WITH SAID FIRST GEAR MEANS, CRANK MEANS INTERFITTED WITH SAID SECOND GEAR TO ALLOW MANUAL ROTATION THEREOF, A FORMING ROLL CARRIED BY THE END OF THE SHAFT EXTENDING THROUGH SAID PLATE, A PIVOTABLE U FRAME CARRIED BY SAID COVER PLATE AND BEING ATTACHED THERETO BY PITOT MEANS, SAID U FRAME BEING SPACED FROM SAID FORMING ROLL, A PAIR OF IDLER ROLLERS CARRIED BY SAID U FRAME, ONE OF SAID ROLLERS BEING ROTATABLE ABOUT A SLEEVE, A SPRING BIASED PLUNGER MEANS CARRIED BY SAID SLEEVE AND HAVING A PLUNGER HEAD ATTACHED AT ONE END THEREOF, BORE MEANS IN SAID COVER PLATE TO RECEIVE OTHER END OF SAID PLUNGER WHEN SAID U FRAME IS PIVOTED TOWARDS SAID FORMING ROLL, SAID PLUNGER BEING REMOVABLE FROM SAID BORE THEREBY TO ALLOW PIVOTING OF SAID U FRAME TO RELEASE THE OTHER ROLLER FROM ITS OPERATIVE POSITION, MARKING MEANS ON SAID COVER PLATE TO INDICATE THE ANGLE OF BEND, POINTER MEANS SLIDABLY CARRIED ABOUT THE PERIPHERY OF SAID CASE TO COOPERATE WITH SAID MARKING MEANS, BAR MEANS CARRIED BY SAID FORMING ROLL, SAID BAR MEANS HAVING STOP MEANS THEREON TO COOPERATE WITH SAID POINTER MEANS WHEREBY OVERBENDING WILL BE AVOIDED. 